Gram positive: Streptococci group A/B/C/G, S. pneumoniae (if susceptible), S. anginosus group, E. faecalis, L. monocytogenes

Gram negative: N. meningitidis

Anaerobic: Actinomyces, Prevotella melaninogenica, Clostridia, Peptostreptococci

Other: T pallidum (syphilis)